Challenge 'out' calls, says study

LINE JUDGING

New York Times

Published 4:00 am, Wednesday, June 24, 2009

When a line judge at Wimbledon rules on a hair-splittingly close call and says the ball is out, the disgruntled player should not only consider challenging the call for review by digital replay system but also consult a recent issue of Current Biology, according to a UC Davis study.

A vast majority of near-the-line shots called incorrectly by Wimbledon line judges have come on balls ruled out that were actually in, according to a study published in October.

To the vision scientist, the finding added to the knowledge of how the human eye and brain misperceive high-speed objects. To the player, it strongly suggests which calls are worth challenging.

The researchers identified 83 missed calls during the 2007 Wimbledon tournament. Seventy of them, or 84 percent, were on balls ruled out - essentially, shots that line judges believed had traveled farther than they actually did.

Called "perceptual mislocalization" by vision scientists, this subconscious bias is known less formally to Wimbledon fans as "You cannot be serious!" - John McEnroe's infamous dissent when, yes, a 1981 shot was ruled out.

The study suggests players should mostly use their limited number of challenges on questionable out calls rather those that are called in.

"What we're really interested in is how visual information is processed, and how it can be used to a player's advantage," said David Whitney, an associate professor at UC Davis' Center for Mind and Brain. "There is a delay of roughly 80 to 150 milliseconds from the first moment of perception to our processing it, and that's a long time."